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From: "dmalcolm at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug middle-end/108988] New: gimple_fold_builtin_fputs doesn't preserve gimple_builtin_call_types_compatible_p Date: Wed, 01 Mar 2023 21:56:52 +0000 [thread overview] Message-ID: <bug-108988-4@http.gcc.gnu.org/bugzilla/> (raw) https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108988 Bug ID: 108988 Summary: gimple_fold_builtin_fputs doesn't preserve gimple_builtin_call_types_compatible_p Product: gcc Version: 13.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: middle-end Assignee: unassigned at gcc dot gnu.org Reporter: dmalcolm at gcc dot gnu.org Target Milestone: --- Whilst working on PR analyzer/107565, I noticed that in this function: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ typedef struct FILE FILE; FILE* fopen (const char*, const char*); int fprintf (FILE *, const char *, ...); #define NULL ((void *)0) void test_2 (void) { int i; for (i = 0; i < 2; ++i) { FILE *fp = fopen ("/tmp/test", "w"); fprintf (fp, "hello"); } } // should report a leak here ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ the fprintf (fp, "hello"); is optimized to: __builtin_fwrite ("hello", 1, 5, fp); but this call has: (gdb) p gimple_builtin_call_types_compatible_p (repl, gimple_call_fndecl (repl)) $23 = false Specifically, the fprintf is optimized to: __builtin_fputs ("hello", fp); Within gimple_fold_builtin_fprintf this has: (gdb) call debug(stmt) __builtin_fputs ("hello", fp); (gdb) p gimple_builtin_call_types_compatible_p (stmt, gimple_call_fndecl (stmt)) $19 = true which is optimized to: (gdb) call debug(repl) __builtin_fwrite ("hello", 1, 5, fp); (gdb) p gimple_builtin_call_types_compatible_p (repl, gimple_call_fndecl (repl)) $23 = false Note how the resulting call has "false" for gimple_builtin_call_types_compatible_p; this is due to argument idx 2 (the 5): (gdb) p i $13 = 2 (gdb) p arg $14 = <integer_cst 0x7fffea7f9ba0> (gdb) call debug_tree(arg) <integer_cst 0x7fffea7f9ba0 type <integer_type 0x7fffea663150 ssizetype> constant 5> In the analyzer I'm checking that gimple_builtin_call_types_compatible_p is true when handling a builtin that it "knows" how to handle, otherwise the analyzer falls back to assuming that the call could have arbitrary side-effects (e.g. fclose-ing the file, hence it stops reporting the leak). Is this a bug in gimple_fold_builtin_fprintf?
next reply other threads:[~2023-03-01 21:56 UTC|newest] Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-03-01 21:56 dmalcolm at gcc dot gnu.org [this message] 2023-03-01 21:57 ` [Bug middle-end/108988] " dmalcolm at gcc dot gnu.org 2023-03-01 22:20 ` [Bug tree-optimization/108988] " pinskia at gcc dot gnu.org 2023-03-01 22:26 ` cvs-commit at gcc dot gnu.org 2023-03-02 9:38 ` jakub at gcc dot gnu.org 2023-03-03 10:20 ` cvs-commit at gcc dot gnu.org 2023-03-03 10:23 ` jakub at gcc dot gnu.org 2023-03-03 22:48 ` cvs-commit at gcc dot gnu.org 2023-03-03 23:16 ` dmalcolm at gcc dot gnu.org
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